Improvement in slide-valves for steam-engines



UNITE STATES ATENT rrrcn.

M. H. BARNES, OF PEORIA, ILLINOIS, ASSIGNOR TO HIMSELF AND A. S. NORTON, OF SAME PLACE.

IMPROVEMENT IN SLIDE-VALVES FOR STEAM-ENGINES.

Specification forming part of Letters Patent No. 40, 34 1. dated October 27, 1803.

To all whom it may concern:

Be it known that I, MATHIAS H. BARNES, of Peoria, in the county of Peoria and State of Illinois, have invented a new and Improved Mode of Balancing and Regulating the Pressure of Slide-Valves; and I do hereby declare the following to be a full and exact description of the same, reference being had to the accompanying drawings, making part of this specification, in which Figure l is a plan of a steam-chest with my invention applied. Fig. 2 is a vertical longitudinal section of the steam chest and ports, taken at the line 00 x, Figs. 1 and 3. Fig. 3 is a vertical transverse section of the same at y 3 Figs. 1 and 2.

Similar letters of reference indicate corresponding parts in the several figures.

This invention relates to that class of valves in which a balancingplate or secondary valve is employed to receive the pressure of the steam in a direction opposite from that in which it bears upon the valve proper, and thus relieve the latter from friction on its seat.

The present improvement consists in regulating the balancing pressure by changing the exposed area of the apertures in the seat of the balancing-valve.

In order to enable others skilled in the art to which my invention appertains to fully understand and use the same, I will proceed to describe its construction and operation.

A represents a part of asteam-cylinder. B is the valve-chest; G, the steam-supply port; D D, the ports communicating from the valvechests to the ends of the cylinder, and E the exhaust port. F represents a slide valve worked by a rod, G, upon which it is adjustably secured by set-nuts g g, in customary manner. The lower part of the said valve may be of common construction, but its upper part is enlarged in the form shown in Fig. 2, to constitute a balancing pressure-plate, F, of larger area than the valve proper, the upper surface of which pressure-plate rests against a seat, H, upon the lower endof an adjustable hollow cylinder, I, Fig. 1, the interior of which may have free communication with the external air, and an area somewhat in excess of that of the steam-ports. In the present illustration the upper valve-seat is held down by set-screws J J in the top B of the valve-chest, bearing upon cushions h it upon the flange or seat H, and supported or fixed in position by a binding-nut, K, working on a screw-thread upon the exterior of the cylinder I. L represents a perforated plate covering the top of the cylinder I. M is an adjustable register, by which the exposed area of the apertures in the plate L may be regulated, as required.

The manner of using the invention is as follows: The valve F F being in position within the chest the hollow cylinder or seat H I is permitted to rest upon it and there held by turning down the set-screws J till they come in contact with the cushions h. By then screwing down the binding-nut K it may be firmly secured in the required position in contact with the upper part of the valve.

The aperture in the secondary valve-seat H being of larger area than the steam-ports beneath the valve F, causes the upward pressure upon the upper plate to more than counterbalance the downward pressure of both the steam and atmosphere, so that by changing the exposed area of the said apertures in the upper valve-seat, H, by means of an adjustable valve of any form, the relative pressure and friction of the upper and undersurfaces of the valve may be equalized and regulated as required. In the present illustration the said adjustable valve consists of a register or screw-cap, M, which, by turning, can be made to limit or increase the area of exposure to any extent required. The form of this regulating device may, however, be varied as circumstances or preference dictate.

By this invention the pressure and friction upon the valveseat are placed under complete control of the engineer, and by the adjustment of the external valve or register, M, may be regulated as required without opening the valve-chest.

The cushions or springs h h afford sufficient play of the parts to compensate for expansion and contraction due to changes of temperature, so that the valve will work equally well under all conditions, and without vertical play.

Having thus described my invention, what I The above specification of my improved claim as new therein, and desire to secure by mode of balancing and regulating the press- Letters Patent, isure of slide-Valves signed this 25th day of July,

Regulating the pressure and friction of a 1863. slide-valve upon its seat by changing the area t M. H. BARNES. of atmospheric exposure of the working-sur- Witnesses: face of the balancing-valve, substantially as OOTAVIUS KNIGHT, herein described. CHARLES SMITH. 

